What is three fourths plus four fifths minus seven tenths

17/20

Step-by-step explanation:

3/4 + 4/5 - 7/10

1. Find the LCD (Least Common Denominator). The LCD is 20.

2. 20/4=5. 5*3=15. So, 3/4 becomes 15/20.

3. 20/5=4. 4*4=16. So, 4/5 becomes 16/20.

4. 20/10=2. 2*7=14. So, 7/10 becomes 14/20.

5. Your new equation is 15/20 + 16/20 - 14/20.

6. Solve from left to right.

7. 15/20 + 16/20= 31/20.

8. 31/20 - 14/20= 17/20.

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)